Electric hot-air furnace



Feb. 5, 1929. 1.701,012

G. J. ROHN ET AL ELEc'rRIc HOT yAIR FURNAGE Filed Sept. 24, 1923 5Sheets-Sheet l ATTORNEY Feb. 5', 1929. Y 1,701,012

G. J. RoHN ET A1.

ELECTRIC HOT AIR FURNAGE Filed sept.24. 192s s sheets-sheet 2 AgoRNEY 4'Feb. 5, 1929. 1,701,012

G. J. ROHN ET AL ELECTRIC HOT AIR FURNAGE Filed sept. 24. 1923 ssheets-sheet 5 ATTORNEY U BY wd @emmen Patented Feb. 5, 1929.

UNITED STATES PATENT OFFICE.

GILBERT J'. ROHN AND ARNOLD PFAU, JR., OF MILWAUKEE, WISCONSIN,ASSIGNORS, BY MESNE ASSIGNMENTS, T GLOBAR CORPORATION, OF NIAGARA FALLS,NEW

YORK, A CORPORATION OF NEW YORK.

ELECTRIC HOT-AIR FURNACE.

Application led September 24, 1923.

Our invention relates to a hot-air furnace, and is particularly designedfor utilizing electricity as the source of energy for supplying heat.

li The objects of the invention are to provide a. hot-air furnace whichis simple, economical and practical, and which utilizes to the maximumadvantage all, or substantially all, of the heat units generated.

Generically, this invention comprises a draft cylinder' in which aheating unit is enclosed. The heat is producedby a resistance elementwhich is relatively small with respect to the cylinder, and tocompensate for the proportional difference, radiator plates are employedto eiiicaciously distribute the heat.

To the accomplishment of the recited objects and others subordinatethereto, the preferred embodiment of our invention resides in the theconstruction and arrangement of parts hereinafter described, illustratedin the accompanying drawings, and embraced within the scope of theappended claims. p

In said drawings Figure 1 is a vertical elevation, partly in section, ofthe furnace embodying our invention.

Figure 2 is a transverse section taken along lines 2-2 of Figure 1, and

Figures 3 and l are detail side elevations of one of the radiatorplates., and the water manifold, respectively.

Figure 5 is a top plan view of Figure 4.

Figure 6 is an enlarged fragmentary elevation of one of the radiatorplates, illustrating the manner of mounting the resistance element.

Figure is a sectional view taken on line 7 7 of Figure 6.

Figure 8 is an enlarged fragmentary elevation, partly in section, of theuppermost supporting connection of the radiator plates.

Figure 9 is a sectional view talren on line 9-9 of Figure 8, and

Figure 10 is a transverse sectional view taken on line 10-10 of Figure8.

Referring to the drawings, and at first 50 more particularly to Figure1, (5) represents a cylindrical casing constructed, preferably, ofgalvanized sheet iron, and suitably connected sind reenforced adjacentthe top,

Serial No. 664,464.

at the bottom, and an intermediate point, by iron rings The upperextremity of the casing is merged into a truncated crown (7) having asubstantially concave top (8) and suitable hot air outlets (9) leadingto registers (not shown). At the bottom, the casing is equipped with acold air inlet (10) and a door (11) for convenience in filling the waterpan (12).

One or more radiators, preferably in the form of substantiallyrectangular shaped plates (13), together with a similarly shaped watermanifold (14), provided with an inlet (15) and an outlet (16), arecombined with suitable electric resistance bars (17) to produce thedesired heat for the furnace. If certain contingencies require that allof the radiators, including the manifold, should be equipped withelectric resistance bars, this could be done with facility. However,actual experiments which we have conducted show conclusively that forordinary requirements, it is necessary to provide only the alternateplates and the manifold with the resistance bars, and this is the mannerin which the disclosure is made in Figures 1 and 2 of the accompanyingdrawings.

As illustrated, the plates have lugs (18) at their inner oppositecorners which are secured at the top to the bars of the heat deflector,or inverted dome, (19) by bolts (20), and at the bottom to the flange(21) of the upright (22), transverse slots (22 a) being formed at thebase of the lugs for receiving nuts (22 b) A separate upright (23) isemployed to sustain the manifold (1li). 'When in place, as exhibited inFigures 1 and 2, the plates (13) and manifold (14) are disposed .in theupper portion of the casing, and radiate from their' inner adjacentedges outwardly to a point near the inner wall of the casing, suflicientspace being allowed between the outer edges of the plates and the wallof the casing to accommodate a. cylinder (24) of asbestos-lined tin, orsimilar heat insulator, as well as to provide for a dead air space (25).The concave top (8) of the crown of the easing is also preferably filledwith a heat insulator, as quartz sand (26).

In accordance with the present showing (see Figures 6 to 8 inclusive),each alternate plate (13) and the manifold (14) arecast with a diagonalslot (27) medially v'vitbin'v mes of which are mounted the resistancebars (l'f- Specifically, opposite ends of the bar are gripped by a clamp(f2.8) which are in turn suspended by coil springs to allow forexpansion and contraction. Screws (30) serve to fasten the springs (29)to a bridge (8l) of fireproof insulation, as tti-:insite asbestos,secured transversely of the terminals of the slot by bolts The screws(30) also serve a connection for ti electric wires (38) and (3f-l) whichare insulated by an asbestos cover and led through conduit to a mutualoutlet box (36). lnterconnections (87) between the electric resistancebars (i7) as required by delta connection, are led through the plain.radiator plates and are supported on them by porcelain bushings (38).

rllhe maximum heat pressure will obviously be exerted at the top of theradiator plates, and it therefore becomes necessary to provide aconstruction which will protect the crown (7) against heat radiation. Weaccomplish this by means of the hereinbefore mentioned heat detlector(19), which not only functions to connect the upper' ends of theradiator plates, but, combined with the concavity (8) of the top of thecrown, leads the hot air into the outlet pipes (9) and reverses thedirection of ascending heat towards the path of incoming air and theradiators.

An electric switch (not shown) can be placed exteriorly of the furnace,or the circuit may be connected with suitable switch mechanism which inturn is controlled by a thermostat (not shown). f

Manifestly, a draft is produced more readly by suction than by pressure,and it is for this reason that the radiators are located the upper partof the casing. Cold air entering through the inlet 10), contacts withthe radiators which are heated by the resistance bars. It will beunderstood in this connection that the plates carrying the resistancebars are heated first, and that the heat thus generated is radiated tothe imperforate plates. As the heat rises it strikes the deflector whichabsorbs and radiates it in vertical and transverse planes and outwardlythroughthe outlets (9) to registers (not shown) in various rooms of thehouse.

le have shown siX radiator units, inclusive of the water manifold, butit is obvious that this arrangement can be varied at will. The precisecontour of the heat deflector, and other structural features, may alsobe altered without departing from the spirit and principle of ourinvention.

What we claim, is

l. A hot air furnace comprising a casing provided with an inlet and anoutlet, plurality of spaced plates supported within said casing andextending longitudinally in the general direction of and exposed to theflow of air through said casing, certain of said plates each having alongitudinal slot extending through the plate, .an electrical resistanceelement mounted within each slot, and electrical connections for saidelements.

2. A hot air furnace comprising a casing provided with an inlet and anoutlet, a plurality of plates radially supported within said casing, thealternate plates having slots, an electrical resistance element mountedwithin each slot, and electrical connections for said elements.

3. A hot air furnace comprising a casing provided with an inlet and anoutlet, a water manifold supported within said casing and also providedwith a water inlet and a water outlet, said manifold having its sidewall provided with a slot therein terminating short of the ends of themanifold, an electrical resistance element mounted within andsubstantially free of the walls of said slot, and electrical connectionsfor said element.

4. An electrically heated appliance comprising a casing, a metalradiator plate having an velongated slot therein and mounted within saidcasing, an electrical resistance elemernJ of bar-shape havingr a smallerdiameter than the width of said slot and being mounted in said slotwith! the body portion of said resistance element free of the walls ofsaid slot, and electrical connections for said resistance element. i

5. An electrically heated appliance comprising a casing, a single-piecewater manifold mounted within said casing and having a water inlet and awater outlet, said manifold being provided with a lengthened slot in theform of an aperture extending wholly through the material of opposedwalls of said manifold, the ends of said slot being defined by hollowwater-containing portions of said manifold, a longitudinally extend ingresistance element mounted in and spaced from the walls of said slot,and electrical connections for said element.

6. An electrically heated air-heating furnace comprising a casing, aradiator plate arranged upright within said casing and having attachmentlugs at opposite corners, and provided with a diagonal slot, anelectrical resistance element mounted within said slot, and electricalconnections for said element.

7. A hot air furnace comprising a casing provided with an inlet and anoutlet, an upright support, a heat deflector, a plurality of radiatorplates lsecured vertically to and between said upright support and saidde- Hector, electrical resistance elements carried by certain of saidplates, and electrical connections for said elements.

8. An electrically heated appliance comprising a casing, a radiatorplate disposed Within said casing and having a yslot therein, anelectric resistance element arranged niedially of said slot, a clamp foropposite ends of said element, a bridge disposed transversely of saidslot, and a yieldable member between the clamp and the bridge.

9. A hot air furnace provided With an inlet and an outlet, a pluralityof radiator plates arranged vertically adjacent the upper portion ofsaid casing, a support for the base of said plates, an inverted domesecured ad- `jacent the top edges of said plates, and a concave top forthe casing, said dome and said concave top serving conjunctively as aheat deflector.

l0. A hot air furnace comprising a oasing provided with an inlet and anoutlet, a plurality of radiator' plates mounted in said casing,electrical resistance elements carried by certa-in of said plates, aheat de* tlector, simulating in contour an inverted truncated cone,secured to the upper edges of said elements below the top ot saidcasing.

l1. A hot air furnace comprising a casing provided with an inlet andoutlets, and a concave top between the outlets, a plurality of radiatorplates mounted in said casing, electrical resistance elements carried bycertain of said plates, a heat defiector, simulating in contour aninverted truncated cone, secured to the upper edges oi'f said elementsbelow the top of said casing, the said cou-- cave top and said deflectorbeing spaced apart and occupying a relatively nested relationship.

12. A hot air iurnace comprisingr a easing provided with an inlet andoutlets, and a concave top between the outlets, a plurality of platesradiating` from the center of the casing, electrical resistance elementscarried by certain oi" said plates, a heat deiector, simulating incontour an inverted truncated cone secured to the upper edges of saidelements below the top of said casing, the said concave top and saiddeector being spaced apart and occupying a relatively nested re*lationship.

13. A hot air furnace comprising a casing provided with an inlet and anoutlet, a plurality of radiator plates arranged perpendicularly andextending substantially onehalf of the height of the casing, and meansfor electrically heating said plates.

Signed at Milwaukee, in the county of GILBERT J. RoHN. ARNOLD PFAU, JR.

